Known apparatus for the production of rubber tubing in predetermined lengths substantially comprise a pair of rotary heads to which the ends of the cores are fixed, the cores being constituted by round bars, supported along their length by a plurality of fixed stands mounted on a suitable supporting structure or bed. In such known apparatus, given the length of the cores and the fixed height of the axes of rotation of the drive heads of the capstans, a correct operating process can only be obtained by utilising cores the radius of which is equal to the transverse distance between the axis of the said drive heads and the support surface of the stands.
Obviously, small differences from this theoretical radius can be admitted without causing excessive working inconveniences; but differences greater than a certain limit can cause an unwanted flexure of the end portions of the cores and, therefore, the risk of oscillation phenomena thereof.
If such oscillations happen it is essential to reduce, proportionately, the speed of rotation of the drive heads, with a corresponding reduction in the working capacity of the apparatus. Moreover, in current systems for the production of rubber tubes, the carriages which normally lie adjacent the beds, and which are utilised for applying the cladding or binding and/or for the introduction of reinforcing strips, fabrics, metal wires and the like, to tubes being produced, are usually carried by a pair of rollers slidable along U-shape guides fixed at the side of the supports of the beds themselves.
This type of support, however, is not able to eliminate the possibility of transverse oscillations of the carriages, with consequent detrimental effect on the accuracy of the operation of the process.